TWI624963B - Oxygen controlled pvd a1n buffer for gan-based optoelectronic and electronic devices - Google Patents

Abstract

The oxygen-controlled PVD AlN buffer layer for GaN-based optoelectronic and electronic devices is described. A method for forming a PVD AlN buffer layer for GaN-based photovoltaic and electronic devices by an oxygen-controlled method is also described. In one example, a method for forming an aluminum nitride (AlN) buffer layer for a GaN-based photovoltaic or electronic device involves reactively sputtering an AlN layer onto a substrate, and reactive sputtering involves placing a physical vapor deposition (PVD) cavity The aluminum target in the room reacts with a nitrogen-containing gas or a plasma based on a nitrogen-containing gas. The method further involves incorporating oxygen into the AlN layer.

Description

AlN buffer layer for oxygen-controlled PVD of GaN-based optoelectronic and electronic devices [Related applications for cross-reference]

This application claims the benefit of US Provisional Patent Application No. 61 / 785,128, filed on March 14, 2013, the entire content of which is incorporated herein by reference.

Embodiments of the present invention relate to the field of III-nitride materials, and more particularly, to the fabrication of gallium nitride-based optoelectronic or electronic devices using an aluminum nitride buffer layer formed by physical vapor deposition (PVD).

III-V materials play an increasingly important role in semiconductors and related industries such as light emitting diodes (LEDs). Generally, it is difficult to generate or deposit a III-V material on a foreign substrate (referred to as heteroepitaxial) without forming defects or cracks. For example, in many applications, high-quality surface protection cannot be applied to selected films (such as gallium nitride films) directly in successively stacked material layer structures. Adding one or more buffer layers between the substrate and the device layer is a way. Although III-V materials are often susceptible to process conditions, care must be taken to avoid such conditions during certain stages of the manufacturing process. However, in many applications, it cannot be avoided directly. Sensitive III-V membranes interact with potentially damaging conditions.

One or more embodiments of the present invention are directed to an aluminum nitride buffer layer formed by physical vapor deposition (PVD).

In one embodiment, a method for forming an aluminum nitride (AlN) buffer layer for a gallium nitride (GaN) -based photovoltaic or electronic device involves reactively sputtering an AlN layer onto a substrate, and reactive sputtering involves placing a physical gas on the substrate. The aluminum-containing target in the phase deposition (PVD) chamber reacts with a nitrogen-containing gas or a plasma based on the nitrogen-containing gas. The method further involves incorporating oxygen into the AlN layer.

In another embodiment, a material stack for a GaN-based optoelectronic or electronic device includes a substrate and an aluminum nitride (AlN) buffer layer on the substrate. The AlN layer has an oxygen concentration of about 1E18 to 1E23 cm ^-3 .

In yet another embodiment, a light emitting diode (LED) device includes a substrate and an aluminum nitride (AlN) buffer layer on the substrate. The AlN layer has an oxygen concentration of about 1E18 to 1E23 cm ^-3 .

In still another embodiment, the GaN-based electronic device includes a substrate and an aluminum nitride (AlN) buffer layer on the substrate. The AlN layer has an oxygen concentration of about 1E18 to 1E23 cm ^-3 .

In another embodiment, the chamber for forming an aluminum nitride (AlN) buffer layer for a GaN-based photovoltaic or electronic device includes a pumping system and a chamber cooling design to achieve a high cost of 1E-7 Torr or less Bottom vacuum and low rise rate at high temperature. The chamber also includes a comprehensive erosion magnetron cathode to configure the AlN film to have consistent target erosion and uniform deposition throughout the wafer within and between the wafer. The chamber also includes a treatment kit and airflow design to configure the The process gas is evenly distributed in the chamber to obtain a uniform AlN composition.

100‧‧‧ Cluster Tool

102, 104, 106‧‧‧ reaction chambers

108‧‧‧Load Lock Room

110‧‧‧carrying case

112‧‧‧ reaction chamber

120‧‧‧LED structure

122‧‧‧ substrate

124‧‧‧ buffer layer

126‧‧‧Combination layer

128‧‧‧MQW structure

130‧‧‧AlGaN layer

132‧‧‧GaN layer

140‧‧‧time mapping of sediments

200‧‧‧ cluster tools

202‧‧‧Sputtering chamber

204, 206, 208‧‧‧ reaction chambers

210‧‧‧Load lock chamber

212‧‧‧carrying case

214‧‧‧Transfer Room

220‧‧‧LED structure

222‧‧‧ substrate

224‧‧‧Aluminum nitride layer

226‧‧‧Floor

228‧‧‧MQW Structure

230‧‧‧AlGaN layer

232‧‧‧GaN layer

240‧‧‧time mapping of sediments

250‧‧‧ Temperature vs. Time

252, 254, 256, 258‧‧‧ zones

300‧‧‧Processing Kit

302, 304‧‧‧Receiver

306‧‧‧shielded

308‧‧‧DTESC

310‧‧‧ Target

312‧‧‧Dark area shielding

314‧‧‧ spacer

316‧‧‧ cover ring

318‧‧‧ sedimentary ring

350‧‧‧ Power Transmission Source

352‧‧‧RF matching

354‧‧‧RF Feed

356‧‧‧Source Distribution Board

358‧‧‧ Ground Shield

360‧‧‧Shell

362‧‧‧Magnet

364‧‧‧DC filter box

366‧‧‧DC feed

368‧‧‧Top plate

370‧‧‧ distribution board

372‧‧‧ extension block

374‧‧‧axis

376‧‧‧Target

420‧‧‧Exhaust ring

500‧‧‧ equipment

502, 532‧‧‧ chamber

504, 522, 524‧‧‧‧ tube

506‧‧‧spray head

508‧‧‧wall

510‧‧‧Air source

512‧‧‧ Energy

514‧‧‧ Crystal Block

516‧‧‧ substrate

518‧‧‧ precursor source

520‧‧‧heater

526‧‧‧Exhaust

600‧‧‧ computer system

602‧‧‧ processor

604, 606, 618‧‧‧Memory

608‧‧‧ network interface device

610‧‧‧video display unit

612‧‧‧Text input device

614‧‧‧ cursor control device

616‧‧‧Signal generating device

620‧‧‧Internet

622‧‧‧Software

626‧‧‧Logic

630‧‧‧Bus

631‧‧‧Computer accessible storage media

4100‧‧‧Equipment

4102‧‧‧ Chamber

4103‧‧‧Subject

4104‧‧‧Sprinkler head assembly

4105‧‧‧Exhaust channel

4106‧‧‧ Catheter

4107‧‧‧valve system

4108‧‧‧Processing volume

4109‧‧‧Exhaust port

4110‧‧‧lower volume

4112‧‧‧Vacuum system

4114‧‧‧ Vehicle

4116‧‧‧Concave

4119‧‧‧ dome

4121A, 4121B‧‧‧Lighting

4124‧‧‧Pipeline

4125‧‧‧Gas delivery system

4126‧‧‧Remote Plasma Source

4129‧‧‧ Catheter

4130‧‧‧Valve

4131-4133‧‧‧ Pipeline

4140‧‧‧ substrate

4166‧‧‧Reflector

FIG. 1 illustrates a schematic diagram of a reference cluster tool, a reference LED structure and a reference time versus deposition according to one or more embodiments of the present invention.

FIG. 2A illustrates a schematic diagram of a cluster tool for LED structure manufacturing and a corresponding temperature versus time plot according to an embodiment of the present invention.

FIG. 2B illustrates a light emitting diode (LED) structure and corresponding time versus deposition according to an embodiment of the present invention.

3A to 3C illustrate cross-sections of a processing kit for a PVD chamber according to an embodiment of the present invention.

Figure 3D illustrates a cross section of a power delivery source for a PVD chamber according to an embodiment of the invention.

FIG. 4 is a schematic cross-sectional view of a MOCVD chamber suitable for manufacturing a group III nitride material according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of an HVPE chamber suitable for manufacturing a group III nitride material according to an embodiment of the present invention.

FIG. 6 is a block diagram of an exemplary computer system according to an embodiment of the present invention.

Describes the use of aluminum nitride (AlN) buffer layers formed by physical vapor deposition (PVD) to fabricate gallium nitride-based optoelectronic or electronic devices. The following description refers to numerous specific details, such as processing chamber configuration and material systems, to provide a more thorough understanding of embodiments of the present invention. Those skilled in the art will clearly understand that the embodiments of the present invention can be practiced without these specific details. In other cases unknown The known characteristic structures such as the specific diode configuration are described to avoid making the embodiments of the present invention obscure. In addition, it should be understood that the various embodiments shown in the figures are for illustration only and are not necessarily drawn to scale. In addition, although the embodiments described herein do not explicitly disclose other configurations and configurations, they are still considered to fall within the spirit and scope of the present invention.

One or more embodiments are for aluminum nitride (AlN) buffer layers for oxygen controlled physical vapor deposition (PVD) applications for gallium nitride (GaN) based optoelectronic and electronic devices. Embodiments may also include a metal organic chemical vapor deposition (MOCVD) process for forming a layer on a PVD AlN layer. Embodiments may be directed to a light emitting diode (LED) or a power supply device. Features corresponding to one or more embodiments may include or imply a sapphire substrate, a patterned sapphire substrate, a Si substrate, XRD, wafer bending, film stress, and differential rows.

PVD AlN can be used as a buffer layer for GaN-based LEDs and power supply devices. The device is generated on a foreign substrate, such as a sapphire or silicon substrate. The PVD AlN layer can be used to improve the material quality of the gallium nitride (GaN) layer generated on top of the AlN buffer layer. Improved GaN can be used to improve device performance (such as brightness, IQE, device leakage and ESD (if LED), and high breakdown voltage (if powered device)) and reliability.

To provide context, PVD AlN buffer layers can be used to eliminate substrate pre-baking, low-temperature GaN buffer layers, and most temperature-varying operations in a typical MOCVD-generated sapphire substrate-coated GaN, and can obtain rapidly growing thin device layers. In short, the processing time will be shortened by 1 to 3 hours due to saving cycle time. For the formation of silicon-on-GaN that may require an AlN layer to protect the silicon substrate from gallium attack, combining the epitaxial process and chamber cleaning time, the PVD AlN layer can save about 3 to 6 hours. Reduced process time can significantly increase system output. Therefore, according to the embodiment of the present invention, the crystal quality of PVD AlN directly affects the quality of the GaN material generated on the top.

As described herein, one or more embodiments of the present invention provide process details, systems, chambers, and hardware configurations to achieve repeatedly obtaining AlN buffer layers with better GaN properties.

More specifically, embodiments of the present invention involve introducing oxygen-containing gases to modify properties before, during, or after AlN deposition, including chemical bonding, crystal structure, grain size and shape, and / or AlN / substrate interface, AlN bulk film And AlN surface morphology so that oxygen doped the AlN layer. In this embodiment, not only the oxygen concentration, but also the time and duration of introducing an oxygen carrier gas into the corresponding PVD chamber (for example, to form AlN) will affect the quality of the subsequent formation of the GaN layer deposited thereon.

In one embodiment, the applicable variable depends on whether the initial substrate is planar or patterned (for example, sapphire is used as an example). When the oxygen concentration, flow rate, introduction time, and other parameters (such as temperature, thickness, etc.) are optimized, a very high-quality AlN film can be generated. For example, in a specific embodiment, an AlN film having an XRD (002) FWHM of less than 15 arc seconds and a surface roughness of less than 2 nanometers (nm) (root mean square) can be deposited. As such, in a specific embodiment, generating GaN on a foreign substrate with such a buffer layer can achieve a much lower differential row density and a narrower XRD FWHM (e.g. (002) <100 arc seconds, (102) <150 Arc seconds). In a particular embodiment, the differential row density is less than about 5E8 defects / cm 2. In one embodiment, the FWHM of XRD (002) is about 50-250 arc seconds. In one embodiment, the FWHM of the XRD (102) is about 70-250 arc seconds. Present invention The embodiment also aims at optimizing the hardware, so that it has the ability to control the temperature and gas composition with high deposition rate and high precision, so as to uniformly modify the properties of the AlN interface, the body and the surface, so as to ensure that the wafer and the wafer have the same High-quality GaN.

The LED or power supply device manufacturing method may include forming a gallium nitride buffer layer between the substrate and the undoped and / or doped gallium nitride device layer. In the embodiment described herein, an aluminum nitride buffer layer is used to replace the gallium nitride buffer layer between the substrate and the undoped and doped gallium nitride device layer. The aluminum nitride layer can be formed by sputtering deposition in a PVD process. This is very different from the traditional fabrication of a Group III nitride buffer layer in a metal organic vapor deposition (MOCVD) chamber, a molecular beam epitaxy (MBE) chamber, or a hydride vapor epitaxy (HVPE) chamber. The aluminum nitride layer can be formed from an aluminum nitride target placed in a PVD chamber by non-reactive sputtering, or the aluminum nitride layer can be formed from an aluminum target placed in a PVD chamber, reactively sputtered, and reacted with nitrogen. Gas or plasma reaction based on nitrogen-containing gas.

According to one or more embodiments, process conditions for a PVD AlN buffer layer for a GaN-based device are described herein. One or more embodiments described herein enable higher yields of multi-chamber manufacturing tools for LED or power supply device manufacturing. In addition, by replacing the gallium nitride buffer layer with an aluminum nitride layer formed by adding PVD, the entire undoped and doped gallium nitride device layer can be made thin. In a specific example, the undoped portion may be thinned or eliminated entirely. In addition, the receiving substrate, such as a sapphire substrate, can be cleaned by preliminary sputtering in the same PVD deposition chamber used to deposit the aluminum nitride layer. In addition, since the PVD aluminum nitride layer can be formed at a temperature lower than 300 ° C, the overall thermal budget for LED or power supply device manufacturing can be reduced. In contrast, a typical gallium nitride or aluminum nitride MOCVD buffer layer is formed between 500 ° C and 600 ° C. One or more embodiments described herein enable such things as undoped and / or Materials such as n-doped gallium nitride have faster deposition rates, such as twice the generation rate. In some embodiments, since the undoped and / or n-doped gallium nitride layer is formed on the aluminum nitride (AlN) buffer layer, a better crystal orientation and morphology relationship is provided for undoped and / or Or n-type doped gallium nitride is formed on it, so a faster rate can be achieved. One or more embodiments described herein can improve the crystal quality of gallium nitride by forming gallium nitride on the aluminum nitride buffer layer formed by PVD.

Embodiments of the present invention can improve the benchmark system or method developed by the currently described systems and methods. For example, FIG. 1 illustrates a schematic diagram of a reference cluster tool, a reference LED structure, and a reference time versus deposition according to one or more embodiments of the present invention.

Referring to FIG. 1, the reference cluster tool 100 includes an undoped and / or n-type gallium nitride MOCVD reaction chamber 102 (MOCVD1: u-GaN / n-GaN), a multiple quantum well (MQW) MOCVD reaction chamber 104 ( MOCVD2: MQW) and p-type gallium nitride MOCVD reaction chamber 106 (MOCVD3: p-GaN). The reference cluster tool 100 may also include a load lock chamber 108, a carrier cassette 110, and optionally additional undoped and / or n-type gallium nitride MOCVD reaction chamber 112 for a large number of applications, all of which are depicted in Figure 1 .

The reference LED structure 120 includes a stack of various material layers, many of which include III-V materials. For example, the reference LED structure 120 includes a silicon or sapphire substrate 122 (substrate: sapphire, Si), a 20 nm thick buffer layer 124 (LT buffer layer), and an approximately 4 micron thick undoped / n-type gallium nitride composite layer 126 (u-GaN / n-GaN). The buffer layer 124 may be a gallium nitride layer formed at a lower processing temperature. The buffer layer 124 and the undoped / n-type gallium nitride combination layer 126 are in the undoped and / or n-type gallium nitride MOCVD reaction chamber of the reference cluster tool 100 Formed in 102. The reference LED structure 120 also includes an MQW structure 128 having a thickness of 30-500 nanometers. The MQW structure 128 is formed in the MQW MOCVD reaction chamber 104 of the reference cluster tool 100. The reference LED structure 120 also includes a p-type aluminum gallium nitride layer 130 (p-AlGaN) with a thickness of about 20 nm and a p-type gallium nitride layer 132 (p-GaN) with a thickness of 50-200 nm. The p-type aluminum gallium nitride layer 130 and the p-type gallium nitride layer 132 are formed in the p-type gallium nitride MOCVD reaction chamber 106 of the reference cluster tool 100.

The reference time versus deposition plot 140 represents the use of the chamber of the reference cluster tool 100. The generation time for forming the MQW structure 128 in the MQW MOCVD reaction chamber 104 is about 2 hours. In addition, the generation time for forming the p-type aluminum gallium nitride layer 130 and the p-type gallium nitride layer 132 in the p-type gallium nitride MOCVD reaction chamber 106 is about 1 hour. Meanwhile, the formation time of forming the buffer layer 124 and the undoped / n-type gallium nitride combined layer 126 in the undoped and / or n-type gallium nitride MOCVD reaction chamber 102 is about 3.5 hours. It takes about 1 hour for the chamber cleaning of the chamber 102. Therefore, in general, the cycle time for manufacturing the reference LED structure 120 in the reference cluster tool 100 is limited by the cycle time of the undoped and / or n-type GaN MOCVD reaction chamber 102, which is about 4.5 hours. It should be understood that the cleaning time may (but not necessarily) include shutdown time, plus cleaning time, plus response time. It should also be understood that the above represent only average values, as cleaning may not occur between each chamber use.

As shown in Figure 1, the following provides a reference timing for LED material deposition, which is specific to the formation of the buffer layer 124 and the undoped / n Type gallium nitride combination layer 126. For example, the generation time of about 3.5 hours can be divided into 10 minutes of high-temperature treatment Sapphire Stone substrate, 5 minute low-temperature formation buffer layer, 10 minutes buffer layer annealing operation, 30 minutes generation recovery operation, 2 hours undoped / n-type gallium nitride composite layer formation operation, and 30 minutes temperature changing and stable operation (E.g. temperature change at 2 ° C-3 ° C / second).

Referring to the reference system and method described in FIG. 1, the reference method causes an unbalanced time flow in each functional layer of the LED. For example, the buffer layer 124 and the undoped / n-type gallium nitride composite layer 126 are formed in the undoped and / or n-type gallium nitride MOCVD reaction chamber 102 for 3.5 hours, and are formed in the MQW MOCVD reaction chamber 104. The MQW structure 128 is 2 hours, and the p-type aluminum gallium nitride layer 130 and the p-type gallium nitride layer 132 are formed in the p-type gallium nitride MOCVD reaction chamber 106 for 1 hour. In addition, as described above, in the undoped and / or n-type gallium nitride MOCVD reaction chamber 102, another one hour of chamber cleaning (perhaps including pumping time) is required between each run. Additional cleaning of the chamber is necessary to avoid substrate contamination. As such, gradually generating structures 120 from three MOCVD chambers will cause the MQW MOCVD reaction chamber 104 and p-type gallium nitride MOCVD reaction chamber 106 to have a large amount of idle time, thereby reducing the overall yield of the system 100.

In one aspect of the present invention, by replacing one or a part of the MOCVD material generating capability or operation with a PVD sputtering deposition capability or operation, the yield of a cluster system for manufacturing an LED or a power supply device structure can be increased. For example, FIG. 2A illustrates a schematic diagram of a cluster tool for manufacturing LED structures and corresponding temperature versus time according to an embodiment of the present invention. FIG. 2B illustrates an LED structure and corresponding time versus deposition according to an embodiment of the present invention.

Referring to FIG. 2A, the cluster tool 200 includes a PVD aluminum nitride sputtering chamber 202 (PVD AlN), undoped and / or n-type gallium nitride MOCVD reaction Stress chamber 204 (MOCVD1: u-GaN / n-GaN), multiple quantum well (MQW) MOCVD reaction chamber 206 (MOCVD2: MQW), and p-type gallium nitride MOCVD reaction chamber 208 (MOCVD3: p-GaN) . The cluster tool 200 may also include a load lock chamber 210, a carrier cassette 212, and a transfer chamber 214. The above-mentioned chambers are all depicted in FIG. 2A.

Therefore, according to an embodiment of the present invention, the multi-chamber system includes a PVD chamber having a metal or composite aluminum target and a chamber suitable for depositing undoped and / or n-type gallium nitride or both. In one embodiment, the target of the PVD chamber is composed of aluminum nitride. In this embodiment, it is not necessary to use reactive sputtering, because the target is composed of the same material as the one to be deposited. However, in an alternative embodiment, a target composed of aluminum is used, and aluminum nitride is reactively sputtered from the aluminum target using or in the presence of a nitrogen source. In one embodiment, as shown in FIG. 2A, the chamber suitable for depositing undoped or n-type gallium nitride is a MOCVD chamber. However, in an alternative embodiment, the chamber suitable for depositing undoped or n-type gallium nitride is a hydride vapor phase epitaxy (HVPE) chamber. In one embodiment, as shown in FIG. 2A, a PVD chamber and a chamber suitable for depositing undoped or n-type gallium nitride are included in the cluster tool configuration. However, in an alternative embodiment, the PVD chamber and the chamber suitable for depositing undoped or n-type gallium nitride are included in an in-line tool configuration. The PVD application deposition process described herein can be performed at about standard room temperature, or can be performed at higher temperatures.

Referring to FIG. 2B, the LED structure 220 includes a stack of various material layers, and many material layers include III-V materials. For example, the LED structure 220 includes a silicon or sapphire substrate 222 (substrate: sapphire, Si) and an aluminum nitride layer 224 (AlN) having a thickness of about 10-200 nm. The aluminum nitride layer 224 is based on the PVD of the cluster tool 200 The aluminum nitride sputtering chamber 202 is formed by sputtering deposition. The LED structure 220 also includes an undoped / n-type gallium nitride combination or an n-type GaN only layer 226 (n-GaN) that is about 4 microns thick. The undoped / n-type gallium nitride combination or the n-type gallium nitride unique layer 226 is formed in the undoped and / or n-type gallium nitride MOCVD reaction chamber 204 of the cluster tool 200. The LED structure 220 also includes an MQW structure 228 having a thickness of 30-500 nanometers. The MQW structure 228 is formed in the MQW MOCVD reaction chamber 206 of the cluster tool 200. In one embodiment, the MQW structure 228 is composed of one or more field pairs of an InGaN well / GaN barrier material layer. The LED structure 220 also includes a p-type aluminum gallium nitride layer 230 (p-AlGaN) with a thickness of about 20 nanometers and a p-type gallium nitride layer 232 (p-GaN) with a thickness of 50-200 nanometers. The p-type aluminum gallium nitride layer 230 and the p-type gallium nitride layer 232 are formed in the p-type gallium nitride MOCVD reaction chamber 208 of the cluster tool 200. It should be understood that the above thicknesses or thickness ranges are merely exemplary embodiments, and other appropriate thicknesses or thickness ranges are also considered to fall within the spirit and scope of the embodiments of the present invention.

The time vs. deposition map 240 represents the chamber use of the cluster tool 200. The generation time for forming the MQW structure 228 in the MQW MOCVD reaction chamber 206 is about 2 hours. The formation time of forming the p-type aluminum gallium nitride layer 230 and the p-type gallium nitride layer 232 in the p-type gallium nitride MOCVD reaction chamber 208 is about 1 hour. According to an embodiment of the present invention, the generation time of forming the undoped / n-type gallium nitride combination or the n-type gallium nitride unique layer 226 in the undoped and / or n-type gallium nitride MOCVD reaction chamber 204 is only For about 2 hours. It takes about 1 hour for the chamber cleaning of the chamber 204. However, it should be understood that the cleaning time may include shutdown time, plus cleaning time, and response time. It should also be understood that the above represent only average values, as cleaning may not occur between each chamber use.

Therefore, a buffer layer is not formed in the MOCVD chamber for forming the gallium nitride layer 126, such as the buffer layer 124 in FIG. 1, but instead includes an aluminum nitride buffer layer 224 and is formed in another chamber, especially PVD nitride. Aluminum sputtering chamber 202. Although excluding pumping time (from about 400 Torr to about 10 ^-8 Torr), AlN generation may take about 5 minutes, but formation in a chamber different from MOCVD chamber 1 may increase the yield of cluster tool 200. For example, in general, the cycle time for manufacturing the LED structure 220 in the cluster tool 200 is again limited by the cycle time of the undoped and / or n-type gallium nitride MOCVD reaction chamber 204, which corresponds to 4.5 hours of the reference system. For about 3 hours. In this way, excluding the three MOCVD chambers and gradually generating the structure 220 with one PVD chamber, the idle time of the MQW MOCVD reaction chamber 206 and the p-type gallium nitride MOCVD reaction chamber 208 is much less, thereby improving the overall system 200 Yield. For example, in one embodiment, the tool output is increased from about 5.3 runs per day to about 8 runs per day, indicating that the output can be increased by about 50%.

Referring again to Figure 2A, the figure provides a representative temperature versus time plot 250 for fabricating LED structures in the cluster tool 200. The region 252 of the drawing 250 is specific to forming an undoped / n-type gallium nitride combination or n-type gallium nitride unique layer 226 in the undoped and / or n-type gallium nitride MOCVD reaction chamber 204. It is only necessary to change the temperature once in this area (from about 1100 ° C to about 400 ° C). This single temperature change event requirement is in stark contrast to the timing described above for forming the buffer layer 124 and the undoped / n-type gallium nitride composite layer 126 in the undoped and / or n-type GaN MOCVD reaction chamber 102. . In this case, the chamber starts with high temperature for substrate processing, cooling for buffer layer manufacturing, rising temperature for gallium nitride deposition, and finally cooling again to achieve stability. It should be noted that in both cases, the specific The regions 254 and 256 for forming MQW and p-GaN are almost the same. In one embodiment, referring to the area 258 of the drawing 250, the temperature versus time for PVD formation of aluminum nitride can cover a high temperature (HT) or low temperature (LT) process, which is approximately 20 ° C to 1200 ° C.

In addition to increasing the yield of the cluster tool 200, the tool configuration of one PVD chamber plus three MOCVD chambers has additional advantages. For example, since less reactive gas needs to be delivered to the first MOCVD chamber, costs can be saved. Compared with the construction time and complexity of the MOCVD chamber dedicated to the buffer layer and the device layer like the chamber 102 of the reference cluster tool 100, the processing and design of the PVD chamber is simpler. In the case where the above process can reduce the thickness of the undoped gallium nitride portion in the device layer 226, a simpler and complete etch-back process can be performed. This also saves material and operating costs while reducing cycle time. In addition, by replacing the gallium nitride buffer layer with an aluminum nitride buffer layer, the defect rate of the active layer of a device (such as an LED device or a power supply device) can be reduced.

Therefore, according to an embodiment of the present invention, the multi-chamber system includes a PVD chamber having an aluminum nitride target and a first MOCVD chamber for depositing undoped or n-type gallium nitride. The multi-chamber system also includes a second MOCVD chamber for depositing a multiple quantum well (MQW) structure and a third MOCVD chamber for depositing p-type aluminum gallium nitride or p-type gallium nitride or both. In one embodiment, a PVD chamber with an aluminum nitride target is used for non-reactive sputtering of aluminum nitride. In this particular embodiment, the PVD chamber is used to non-reactively sputter aluminum nitride at a low or slightly higher temperature of about 20 ° C to 200 ° C. In another specific embodiment, the PVD chamber is used for non-reactive sputtering of aluminum nitride at a high temperature of about 200 ° C to 1200 ° C. In an alternative embodiment, the PVD chamber is for use with nitrogen Gas or plasma derived from nitrogen-containing gas, reactive sputtering aluminum target.

Regardless of the deposition temperature, the PVD-deposited aluminum nitride layer suitable for inclusion in the LED structure 220 may at some times need to be exposed to a high temperature of about 400 ° C to 1400 ° C, such as about 900 ° C, to achieve the necessary material properties (such as appropriate defects) Density, grain size, crystal orientation, etc.). According to an embodiment of the present invention, before manufacturing the additional layer on the aluminum nitride layer, a rapid thermal processing (RTP) process is performed to process the PVD deposited aluminum nitride layer. The RTP chamber is related to the manufacturing process of the LED structure 220 to some extent. In one embodiment, the tool (such as a cluster tool or an in-line tool including PVD and three MOCVD chambers) also includes an RTP chamber. However, in an alternative embodiment, the RTP process is performed in a PVD chamber. In another alternative embodiment, the laser annealing capability is related to the manufacturing process of the LED structure 220 described above.

Next, in one aspect of the present invention, process conditions for forming a physical vapor deposition (PVD) aluminum nitride (AlN) buffer layer are described. This buffer layer may be included in, for example, a GaN-based device. In one embodiment, a parametric process window is provided to deposit AlN with certain characteristics and properties.

Taking light-emitting diode (LED) manufacturing as an example, the manufacturing process usually includes forming a low-temperature buffer layer on a substrate by using metal organic chemical vapor deposition (MOCVD). After the buffer layer is deposited by MOCVD, an active device layer is usually formed, such as an undoped, Si-doped n-type MQW, and a Mg-doped p-type GaN layer. The substrate pre-baking is generally performed at a high temperature (for example, higher than about 1050 ° C). In contrast, the buffer layer is generally deposited at a low temperature (for example, about 500 ° C to 600 ° C). The process can account for about 10% -30% of the overall MOCVD process time. Using off-site deposition of the buffer layer can increase the yield of MOCVD. So in one embodiment, as described later In detail, an off-site deposited AlN buffer layer formed by PVD is described. In one embodiment, the PVD process is performed in different chambers.

In one embodiment, process conditions are provided to form a substrate having an AlN buffer layer (template), which is suitable for use in GaN device manufacturing. In this embodiment, oxygen-controlled deposition of a PVD AlN buffer layer is performed.

In one embodiment, the AlN buffer layer is formed by reactive sputtering from an aluminum-containing target placed in a PVD chamber and reacting with a nitrogen-containing gas or a plasma based on a nitrogen-containing gas. In one embodiment, oxygen incorporation is also performed. In an exemplary embodiment, oxygen incorporation is performed with one or more (or a combination) of the following operations and conditions: (1) flowing an oxygen-containing gas into the PVD chamber, such as O ₂ , H ₂ O, CO, CO _2. NO, NO ₂ , O ₃ , or the above gas composition, but not limited to this; (2) Before, during and / or after turning on the plasma for deposition, inflow of oxygen-containing gas to use the oxygen absorption Conditioning chambers, processing kits and targets, and / or having the optimal amount of oxygen incorporated into the AlN / substrate interface, the AlN block film and the AlN surface, making it suitable for high-quality GaN generation; and (3) precise control Oxygen-containing gas flow rate, introduction time and duration to ensure uniform modification of the interface between AlN and foreign substrates, AlN film and AlN surface. In a specific embodiment, the amount of oxygen (O) incorporated into the AlN film is about 1E18 to 1E23 atoms / cubic centimeter. In one embodiment, the substrate with AlN deposited thereon is, for example, sapphire, silicon (Si), silicon carbide (SiC), diamond-on-silicon, zinc oxide (ZnO), lithium aluminum oxide (LiAlO ₂ ), or magnesium oxide (MgO). ), Gallium arsenide (GaAs), copper and tungsten (W), but not limited to this. The substrate can be planar or pre-patterned.

In one embodiment, the optimized hardware for the oxygen-controlled deposition of PVD AlN buffer layers includes one or more of the following configurations: (1) pumping system, chamber vacuum conditioning Design and chamber cooling design to achieve high background vacuum (for example, 1E-7 Torr or below), and low vacuum leakage and pressure rise rate (for example, 2500 Nato) at high temperature (for example, 350 ° C or above) Ears / minute or less); (2) comprehensively erode the magnetron cathode to ensure that the AlN film has consistent target erosion within the wafer and between wafers and uniformly deposits all over the sample carrier; (3) processing kit And airflow design to ensure that the process gas including O gas is evenly distributed in the chamber to obtain the optimal AlN composition; (4) high temperature biased electrostatic chucks to ensure rapid and uniform heating of the wafer; and (5) Oxygen-doped Al target material, so that the optimal amount of oxygen is uniformly incorporated into the deposited AlN film to ensure that high-quality GaN is generated on top (for example, in one embodiment, the doped oxygen concentration of the aluminum target material is (About 1 ppm to 10000 ppm). In one embodiment, the chamber process is used to ensure uniform and adequate conditioning of the processing kit and target, and to provide reproducible PVD AlN properties between passes. It should be understood that in this embodiment, the number of pass cycles can be determined from each run to the life of each target or processing kit. The one or more aspects will be described later with reference to FIGS. 3A to 3D.

In this embodiment, the above conditions and hardware are used to deposit high-quality AlN to achieve high process reproducibility between batches and wafers and high uniformity within the wafer. High-quality GaN (FWHM of XRD (002) <100 arc-seconds, and / or FWHM of XRD (102) <150 arc-seconds) can be generated on top of AlN, a process that proves reproducible. In a specific embodiment, the differential row density of GaN is less than about 5E8 defects / cm 2. In one embodiment, the FWHM of XRD (002) is about 50-250 arc seconds. In one embodiment, the FWHM of the XRD (102) is about 70-250 arc seconds. In one embodiment, the above unique hardware and process can provide ultra-high quality AlN and GaN with high yield and reproducibility.

Exemplary tool platform embodiments suitable for accommodating a PVD chamber and three MOCVD chambers include the Opus ^™ AdvantEdge ^™ system or the Centura ^™ system, both of which are sold by Applied Materials, Inc. of Santa Clara, California, USA. Embodiments of the invention further include an integrated measurement (IM) chamber as a component of a multi-chamber processing platform. The IM chamber can provide control signals to allow proper control of integrated deposition processes, such as multi-segment sputtering or epitaxial growth processes as described herein. The IM chamber may include measuring equipment suitable for measuring various film properties, such as thickness, roughness, composition, and can further characterize grating parameters in an automated manner under vacuum, such as critical dimension (CD), sidewall angle (SWA ), Feature height (HT). Examples include, but are not limited to, optical techniques such as reflection and scattering. In a particularly advantageous embodiment, in-vacuum optical CD (OCD) technology is employed, in which the properties of the gratings formed in the starting material are monitored as sputtering and / or epitaxial growth proceeds. In other embodiments, the measurement operation is performed in the processing chamber, such as in situ in the processing chamber, rather than in a different IM chamber.

A multi-chamber processing platform (such as the cluster tool 200) may further include a selective substrate alignment chamber and a load lock chamber of a support cassette, both of which are coupled to a transfer chamber including a machine handler. In an embodiment of the present invention, the controller appropriately controls the multi-chamber processing platform 200. The controller can be any type of general-purpose data processing system for industrial settings to control various sub-processors and sub-controllers. Generally, a controller includes a central processing unit (CPU) that is communicatively connected to memory and input / output (I / O) circuits among other common components. In an example, the controller may perform or otherwise initialize one or more operations of any of the methods / processes described herein. Any computer code that performs and / or initializes Can be embodied as a computer program product. The computer program products described herein can be executed by computer-readable media (such as floppy disks, optical disks, DVDs, hard drives, random access memory, etc.).

Suitable PVD chambers for the processes and tool configurations included herein may include the Endura® Impulse ^™ PVD system sold by Applied Materials, Inc. of Santa Clara, California. Endura PVD system provides better electromigration resistance and surface topography, low cost of ownership and high system reliability. The PVD process can be completed in the system by generating the flux of directional deposited species in the processing chamber with the necessary pressure and appropriate target-to-wafer distance. Chambers compatible with in-line systems (such as ARISTO chambers) are also sold by Applied Materials, Inc. of Santa Clara, California, and provide automatic loading and unloading capabilities and magnetic carrier transport systems to significantly reduce cycle times. The AKT-PiVot 55KV PVD system is also sold by Applied Materials, Inc. of Santa Clara, California, and has a vertical platform for sputter deposition. The modular structure of the AKT-PiVot system gives faster cycle times and can be configured with multiple configurations to maximize production efficiency. Unlike traditional in-line systems, AKT-PiVot's parallel processing capabilities can eliminate bottlenecks caused by different process times for each film layer. The cluster-like configuration of the system also allows continuous operation during individual module maintenance. Including the rotating cathode technology can make the target utilization rate about 3 times higher than the conventional system. The PiVot system's deposition module features a pre-sputtering unit that uses only one substrate to condition the target, while other systems require up to 50 substrates to achieve the same result.

In one aspect of the invention, designing a suitable processing kit is important to the pulsed DC or RF chamber functionality of the PVD processing chamber. In an example, FIGS. 3A to 3C illustrate a method for PVD according to an embodiment of the present invention. Section of the chamber's processing kit. Figure 3D illustrates a cross section of a power delivery source for a PVD chamber according to an embodiment of the invention.

Referring to FIGS. 3A to 3C, the processing kit 300 for a PVD chamber includes a first part (FIG. 3A), the first part having an upper responder 302, a lower responder 304, a lower shield 306, and a DTESC 308. The processing kit 300 for a PVD chamber also includes a second part (FIG. 3B), which has a target 310, a dark area shield 312, and an Al partition 314. The processing kit 300 for a PVD chamber also includes a third portion (FIG. 3C), which has a cover ring 316 and a deposition ring 318.

Referring to FIG. 3D, a power delivery source 350 for a PVD chamber includes an RF match 352 and an RF feed 354. A source distribution board 356 (such as an aluminum source distribution board) and a ground shield 358 (such as an aluminum metal sheet) and a metal housing 360 and a ring magnet 362 are also included. The power transmission source 350 also includes a DC filter box 364 and a DC feed 366. The top plate 368 and the distribution plate 370 and the extension block 372, the shaft 374 and the target 376 are also included.

An example of a MOCVD deposition chamber suitable for use as one or more of the MOCVD chambers 204, 206, or 208 will be described with reference to FIG. FIG. 4 is a cross-sectional view of a MOCVD chamber according to an embodiment of the present invention.

The apparatus 4100 shown in FIG. 4 includes a chamber 4102, a gas delivery system 4125, a remote plasma source 4126, and a vacuum system 4112. The chamber 4102 includes a chamber body 4103 that surrounds the processing volume 4108. The spray head assembly 4104 is provided at one end of the processing volume 4108, and the substrate carrier 4114 is provided at the other end of the processing volume 4108. The lower dome 4119 is provided at one end of the lower volume 4110, and the substrate carrier 4114 is provided at the other end of the lower volume 4110. Substrate carrier 4114 series It is shown in the processing position, but the substrate carrier 4114 can be moved to a lower position, such as loading or unloading the substrate 4140. An exhaust ring 420 may be provided around the substrate carrier 4114 to help prevent deposition in the lower volume 4110 and help guide exhaust from the chamber 4102 to the exhaust port 4109. The lower dome 4119 may be made of a transparent material, such as high-purity quartz, to allow light to pass through and radiantly heat the substrate 4140. Radiation heating can be provided by a plurality of internal lamps 4121A and external lamps 4121B provided under the lower dome 4119. The reflector 4166 can be used to assist the control chamber 4102 to expose the radiant energy provided by the internal and external lamps 4121A, 4121B. The additional lamp ring can also be used to control the temperature of the substrate 4140.

The substrate carrier 4114 may include one or more recesses 4116, and one or more substrates 4140 may be placed in the recesses 4116 during processing. The substrate carrier 4114 may carry six or more substrates 4140. In one embodiment, the substrate carrier 4114 carries eight substrates 4140. It should be understood that more or fewer substrates 4140 can be carried on the substrate carrier 4114. A typical substrate 4140 may include sapphire, silicon carbide (SiC), silicon, or gallium nitride (GaN). It should be understood that other types of substrates 4140 can also be processed, such as glass substrates 4140. The substrate 4140 may have a diameter of 50 millimeters (mm) to 100 mm or more. The size of the substrate carrier 4114 may be 200 mm to 750 mm. The substrate carrier 4114 may be made of a variety of materials, including SiC or SiC-coated graphite. It should be understood that other sizes of substrates 4140 can be processed within the chamber 4102 according to the processes described herein. Compared to a conventional MOCVD chamber, the showerhead assembly 4104 allows for more uniform deposition over more substrates 4140 and / or larger substrates 4140, thereby increasing throughput and reducing processing costs per substrate 4140.

During processing, the substrate carrier 4114 can be rotated about an axis. In one embodiment, the rotation speed of the substrate carrier 4114 is about 2 RPM (revolutions per minute) to about 100 RPM. In another embodiment, the rotation speed of the substrate carrier 4114 is about 30 RPM. The rotation of the substrate carrier 4114 helps to provide uniform heating of the substrates 4140 and uniform contact of the processing gas with each substrate 4140.

A plurality of internal and external lamps 4121A, 4121B can be arranged in concentric circles or zones (not shown), and each lamp zone can be individually powered. In one embodiment, one or more temperature sensors (such as a pyrometer (not shown)) may be provided in the spray head assembly 4104 to measure the temperature of the substrate 4140 and the substrate carrier 4114, and the temperature data may be sent to A controller (not shown). The controller can adjust the power of each lamp area to maintain a predetermined temperature distribution throughout the substrate carrier 4114. In another embodiment, the power of each lamp area can be adjusted to compensate for non-uniformity in the precursor stream or precursor concentration. For example, if the substrate carrier 4114 has a low concentration of precursors in the area near the external lamp area, the power applied to the external lamp area can be adjusted to help compensate for the precursor depletion in this area.

The internal and external lamps 4121A, 4121B can heat the substrate 4140 to a temperature of about 400 ° C to about 1200 ° C. It should be understood that the present invention is not limited to the use of an array of internal and external light fixtures 4121A, 4121B. Any suitable heating source can be used to ensure proper application of a suitable temperature to the chamber 4102 and the contained substrate 4140. For example, in another embodiment, the heating source may include a resistive heating element (not shown), which may be in thermal contact with the substrate carrier 4114.

The gas delivery system 4125 may include multiple gas sources, or depending on the operating process, some sources may be liquid sources rather than gases. In this case, the gas delivery system may include a liquid injection system or other device (such as foaming) Device) to evaporate the liquid. The steam is then mixed with the carrier gas before being delivered to the chamber 4102. Such as precursor gas, carrier gas, purge gas, cleaning / etching gas, etc. Different gases can be supplied from the gas delivery system 4125 to individual supply lines 4131, 4132, 4133 and to the sprinkler head assembly 4104. The supply lines 4131, 4132, and 4133 may include shut-off valves and mass flow controllers or other types of controllers to monitor and regulate or close the air flow of each line.

The catheter 4129 may receive a cleaning / etching gas from a remote plasma source 4126. The remote plasma source 4126 may receive gas from the gas delivery system 4125 via a supply line 4124, and a valve 4130 may be provided between the sprinkler head assembly 4104 and the remote plasma source 4126. The valve 4130 can be opened to allow the cleaning and / or etching gas or plasma to flow into the sprinkler head assembly 4104 via the supply line 4133, which is suitable as a plasma conduit. In another embodiment, the device 4100 does not include a remote plasma source 4126, and the cleaning / etching gas may be configured using an alternative supply line from a non-plasma cleaning and / or etching gas delivery system 4125 to the sprinkler head assembly 4104. .

The remote plasma source 4126 may be a radio frequency or microwave plasma source suitable for cleaning the chamber 4102 and / or etching the substrate 4140. The cleaning and / or etching gas may be supplied to a remote plasma source 4126 via a supply line 4124 to generate a plasma species, which is disseminated via the conduit 4129 and the supply line 4133 through the sprinkler head assembly 4104 into the chamber 4102. Gases used as cleaning applications may include fluorine, chlorine, or other reactive elements.

In another embodiment, the gas delivery system 4125 and the remote plasma source 4126 are appropriately modified to supply precursor gas to the remote plasma source 4126 to generate plasma species, and the plasma species are dispersed through the sprinkler head assembly 4104 and deposit a CVD layer, such as a III-V film, on the substrate 4140, for example. Generally, the plasma in the state of matter is transmitted by electric energy or electromagnetic waves (e.g. radio frequency waves, microwaves). The process gas (such as precursor gas) is sent to cause the process gas to be at least partially decomposed to form plasma species, such as ions, electrons, and neutral particles (such as free radicals). In one example, the plasma is generated in the inner region of the plasma source 4126 by transmitting electromagnetic energy at a frequency of less than about 100 gigahertz (GHz). In another example, the plasma source 4126 is configured to deliver electromagnetic energy at a frequency of about 0.4 kilohertz (kHz) to about 200 megahertz (MHz), such as a frequency of about 162 megahertz (MHz) and a power level of less than about 4 kilowatts (kW) . The formation of a plasma can enhance the formation and activity of the precursor gas, so that the activated gas that reaches the substrate surface during the deposition process can react quickly to form a film layer with improved physical and electrical properties.

Purge gas (such as nitrogen) may be delivered into the chamber 4102 from the sprinkler head assembly 4104 and / or from an inlet port or pipe (not shown) provided below the substrate carrier 4114 and near the bottom of the chamber body 4103. The purge gas enters the lower volume 4110 of the chamber 4102, and flows upward through the substrate carrier 4114 and the exhaust ring 420 to enter a plurality of exhaust ports 4109. The exhaust ports 4109 are provided around the annular exhaust channel 4105. The exhaust duct 4106 connects the annular exhaust passage 4105 and the vacuum system 4112. The vacuum system 4112 includes a vacuum pump (not shown). The pressure of the chamber 4102 is controlled by a valve system 4107, which controls the rate at which exhaust gas is drawn out of the annular exhaust passage 4105.

An example of the HVPE deposition chamber of the HVPE chamber 204 suitable for use as an alternative embodiment of the above-mentioned chamber 204 (or an alternative embodiment of other chambers) will be described with reference to FIG. 5. FIG. 5 is a cross-sectional view of an HVPE chamber 500 suitable for manufacturing a group III nitride material according to an embodiment of the present invention.

The device 500 includes a chamber 502 surrounded by a cover 504. From the first The processing gas from a gas source 510 is delivered to the chamber 502 via a gas distribution spray head 506. In one embodiment, the gas source 510 includes a nitrogen-containing compound. In another embodiment, the gas source 510 includes ammonia gas. In an embodiment, inert gas, such as helium or nitrogen, may also be introduced via the gas distribution spray head 506 or via the wall surface 508 of the chamber 502. The energy source 512 may be provided between the gas source 510 and the gas distribution spray head 506. In one embodiment, the energy source 512 includes a heater. The energy source 512 can decompose a gas (such as ammonia) from the gas source 510, making the nitrogen in the nitrogen-containing gas more reactive.

To react with the gas from the first source 510, the precursor material may be delivered from one or more second sources 518. The precursor can be delivered to the chamber 502 by passing a reactive gas through and / or through the precursor of the precursor source 518. In one embodiment, the reaction gas includes a chlorine-containing gas, such as chlorine gas. Chlorine-containing gases can react with precursor sources to form chlorides. In order to increase the effectiveness of the reaction of the chlorine-containing gas with the precursor, the chlorine-containing gas may snake through the boat area of the chamber 532 and be heated by the resistance heater 520. By increasing the residence time of the chlorine-containing gas to snake through the chamber 532, the temperature of the chlorine-containing gas can be controlled. By increasing the temperature of the chlorine-containing gas, chlorine can react with the precursor faster. In other words, the temperature is a catalyst for the reaction of chlorine with the precursor.

In order to improve the reactivity of the precursor, the resistive heater 520 in the second chamber 532 in the ship may be used to heat the precursor. The chloride reaction product is then delivered to the chamber 502. The chloride reaction product first enters the tube 522, where the chloride reaction product is uniformly dispersed in the tube 522. The tube 522 is connected to another tube 524. After the chloride reaction product is uniformly dispersed in the first tube 522, it enters the second tube 524. The chloride reaction product then enters the chamber 502, where the chloride reaction product reacts with nitrogen The gases are mixed to form a nitride layer on the substrate 516, and the substrate 516 is placed on the crystal base 514. In one embodiment, the base 514 includes silicon carbide. The nitride layer includes, for example, n-type gallium nitride. Other reaction products, such as nitrogen and chlorine, are emitted via an exhaust device 526.

LEDs and related devices can be made of layers such as III-V films, especially III-nitride films. Some embodiments of the present invention relate to forming a gallium nitride (GaN) layer in a dedicated chamber for manufacturing tools, such as a dedicated MOCVD chamber. In some embodiments of the present invention, the GaN-based binary GaN film, but in other embodiments, the GaN-based ternary film (such as InGaN, AlGaN) or the quaternary film (such as InAlGaN). In at least some embodiments, the group III nitride material layer is epitaxially formed. The III-nitride material layer can be formed directly on the substrate or on a buffer layer placed on the substrate. Other covered embodiments include a p-type doped gallium nitride layer, which is directly deposited on a buffer layer formed by PVD, such as aluminum nitride formed by PVD.

It should be understood that embodiments of the present invention are not limited to the above-mentioned formation of a layer on a selected substrate. Other embodiments may include using any suitable unpatterned or patterned single crystal substrate, and a high quality aluminum nitride layer is sputter deposited on the substrate, for example, in a non-reactive PVD manner. The substrate is, for example, a sapphire (Al ₂ O ₃ ) substrate, a silicon (Si) substrate, a silicon carbide (SiC) substrate, a diamond-on-silicon (SOD) substrate, a quartz (SiO ₂ ) substrate, a glass substrate, a zinc oxide (ZnO) substrate, A magnesium oxide (MgO) substrate and a lithium aluminum oxide (LiAlO ₂ ) substrate are not limited thereto. Any known method such as masking and etching can be used to form a patterned substrate by forming a feature structure (for example, a pillar) on a flat substrate. However, in a specific embodiment, a patterned sapphire substrate (PSS) with a (0001) orientation is used. The patterned sapphire substrate is very suitable for manufacturing a specific type of LED, because the patterned sapphire substrate can improve light extraction efficiency, which is extremely useful for manufacturing a new generation of solid-state light-emitting devices. The substrate selection criteria may include lattice matching to slow down defect formation and thermal expansion coefficient (CTE) matching to reduce thermal stress.

As described above, a group III nitride film can be doped. Group III nitride films can be p-type doped using any p-type dopant, such as magnesium (Mg), beryllium (Be), calcium (Ca), strontium (Sr), or any group I or II with two valence electrons Family elements, but not limited to this. The group III nitride film can be p-type doped to have a conductivity level of 1 × 10 ¹⁶ to 1 × 10 ²⁰ atoms / cm 3. The group III nitride film may be n-type doped using any n-type dopant, such as silicon or oxygen or any suitable group IV or VI element, but is not limited thereto. The group III nitride film can be n-type doped to have a conductivity level of 1 × 10 ¹⁶ to 1 × 10 ²⁰ atoms / cm 3.

It should be understood that the above process may be performed in a dedicated chamber of a cluster tool or other tools with multiple chambers, such as an in-line tool configured to have a dedicated chamber for manufacturing each layer of the LED. It should also be understood that embodiments of the present invention are not necessarily limited to LED manufacturing. For example, in another embodiment, devices other than LED devices, such as field-effect transistor (FET) devices, can be manufactured in the manner described herein, but not limited to this. In such embodiments, a p-type material may not be needed on top of the layer structure. Conversely, n-type or undoped materials can be used instead of p-type layers. It should also be understood that multiple operations, such as various combinations of deposition and / or thermal annealing, can be performed in a single processing chamber.

Embodiments of the present invention may be provided as a computer program product or software. The computer program product may include a machine-readable medium containing storage instructions for programming a computer system (or other electronic device) to perform manufacturing according to the present invention. Cheng. Machine-readable media include any mechanism for storing or transmitting information in a form readable by a machine, such as a computer. For example, machine-readable (e.g., computer-readable) media includes machine (e.g., computer-readable) storage media (e.g., read-only memory (ROM), random access memory (RAM), disk storage media, optical Storage media, flash memory devices, etc.), machines (such as computers) can read transmission media (electronic, optical, sound, or other forms of transmission signals (such as infrared signals, digital signals, etc.)).

FIG. 6 is a machine schematic diagram of an exemplary computer system 600 that can execute a set of instructions to cause the machine to perform any one or more of the methods described herein. In alternative embodiments, the machine may be connected (e.g., a network connection) to a local area network (LAN), a corporate intranet, a corporate extranet, or other machines in the Internet. The machine can be operated by a server or client in a master-slave network environment or as a peer machine in a peer-to-peer (or decentralized) network environment. The machine can be a personal computer (PC), tablet PC, set-top box (STB), personal digital assistant (PDA), mobile phone, network device, server, network router, switch, or bridge, or any device (sequential or sequential (Otherwise) the machine that executes the instruction set, which specifies the machine to perform the action. In addition, although only a single machine is illustrated, the term "machine" should also be treated as including a collection of any machines (such as computers) that individually or collectively execute a set (or sets) of instructions to perform the purposes described herein Any one or more methods. In one embodiment, the computer system 600 is suitable for use as a computer device for related equipment described in FIG. 1, FIG. 2A, FIG. 3A, FIG. 3B, FIG. 4, or FIG. 5.

The exemplary computer system 600 includes a processor 602, main memory 604 (e.g., read-only memory (ROM), flash memory, such as synchronous DRAM (SDRAM) or Rambus DRAM (RDRAM) such as dynamic random access memory (DRAM)), static memory 606 (such as flash memory, static random access memory (SRAM), etc.) and secondary memory 618 (such as Data storage device), the processor 602, the memories 604, 606, 618 communicate with each other through a bus 630.

The processor 602 represents one or more general-purpose processing devices, such as a microprocessor, a central processing unit, and the like. More specifically, the processor 602 may be a complex instruction set computing (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction set (VLIW) microprocessor, or a processor implementing other instruction sets Or a processor that implements a combination of instruction sets. The processor 602 may also be one or more special-purpose processing devices, such as a special application integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), a network processor, and the like. The processor 602 is configured to execute processing logic 626 to perform the operations described herein.

The computer system 600 may further include a network interface device 608. The computer system 600 may also include a video display unit 610 (such as a liquid crystal display (LCD) or a cathode ray tube (CRT)), a text input device 612 (such as a keyboard), a cursor control device 614 (such as a mouse), and a signal generating device 616. (Such as speakers).

The secondary memory 618 may include a machine-accessible storage medium (or more specifically, a computer-readable storage medium) 631, and the machine-accessible storage medium 631 stores one or more of any one or more of the methods or functions described. More sets of instructions (such as software 622). The software 622 may also reside entirely or at least partially in the main memory 604 and / or the processor 602. When the computer system 600 executes the software 622, the main The memory 604 and the processor 602 also constitute a machine-readable storage medium. The software 622 may further be transmitted or received on the network 620 through the network interface device 608.

Although in an exemplary embodiment, the machine-accessible storage medium 631 is shown as a single medium, the term "machine-readable storage medium" should be considered to include a single medium or multiple media (e.g., centralized or decentralized) Database and / or associated caches and servers) to store one or more sets of instructions. The term "machine-readable storage medium" shall also be deemed to include any medium capable of storing or encoding a set of instructions executed by the machine to cause the machine to perform any one or more of the methods of the present invention. Therefore, the term "machine-readable storage medium" should be considered to include, but not be limited to, solid-state memory and optical and magnetic media.

According to an embodiment of the present invention, the non-transitory machine-accessible storage medium has a storage instruction for urging the data processing system to perform a method of forming a PVD AlN buffer layer for GaN-based photovoltaic and electronic devices in an oxygen-controlled manner.

Therefore, an oxygen-controlled PVD AlN buffer layer for GaN-based optoelectronic and electronic devices is disclosed.

Claims (23)

A method for forming an aluminum nitride (AlN) buffer layer for a gallium nitride (GaN) -based optoelectronic or electronic device. The method includes the following steps: reactively sputtering an AlN layer onto a substrate, and the reactive sputtering Comprising reacting an aluminum-containing target placed in a physical vapor deposition (PVD) chamber with a nitrogen-containing gas or a plasma based on a nitrogen-containing gas; and incorporating oxygen into the AlN layer, wherein The step of incorporating oxygen into the AlN layer includes incorporating an oxygen concentration between 1E18 and 1E23 cm ^-3 into the AlN layer. The method according to claim 1, wherein the step of incorporating oxygen is performed by flowing an oxygen-containing gas into the PVD chamber, the oxygen-containing gas being selected from the group consisting of O ₂ , H ₂ O, CO, CO ₂ , NO , NO ₂ , O ₃ and the above composition. The method according to claim 1, wherein the step of incorporating oxygen is performed by flowing an oxygen-containing gas before the aluminum-containing target reacts with the nitrogen-containing gas or the plasma based on a nitrogen-containing gas. . The method according to claim 1, wherein the step of incorporating oxygen is performed by flowing an oxygen-containing gas, and simultaneously reacting the aluminum-containing target with the nitrogen-containing gas or the plasma based on the nitrogen-containing gas. . The method according to claim 1, wherein the step of incorporating oxygen is performed after the aluminum-containing target reacts with the nitrogen-containing gas or the plasma based on a nitrogen-containing gas, and then flows into an oxygen-containing gas. . A material stack for a GaN-based optoelectronic or electronic device. The material stack includes: a substrate; and an aluminum nitride (AlN) buffer layer, the AlN buffer layer is located on the substrate, and an oxygen concentration of the AlN layer is Between 1E18 and 1E23cm ^-3 . The material stack according to claim 6, wherein a part of the oxygen system is included at an AlN / substrate interface. The material stack according to claim 6, wherein a part of the oxygen system is included on an outermost surface of the AlN buffer layer. The material stack according to claim 6, further comprising: a high-quality GaN layer on the AlN buffer layer, the XRD (002) FWHM of the high-quality GaN layer is less than 100 arc seconds and the XRD (102 ) FWHM is less than 150 arc seconds. The material stack according to claim 6, wherein the substrate is selected from the group consisting of sapphire, Si, SiC, diamond-coated Si, ZnO, LiAlO ₂ , MgO, GaAs, copper, and W. A light emitting diode (LED) device includes: a substrate; and an aluminum nitride (AlN) buffer layer, the AlN buffer layer is located on the substrate, and an oxygen concentration of the AlN layer is between 1E18 and 1E23cm ^-3 between. The LED device according to claim 11, wherein a part of the oxygen system includes an AlN / substrate interface. The LED device according to claim 11, wherein a part of the oxygen system is included on an outermost surface of the AlN buffer layer. The LED device according to claim 11, further comprising: a high-quality GaN layer, the high-quality GaN layer is located on the AlN buffer layer, and the XRD (002) FWHM of the high-quality GaN layer is less than 100 arc seconds and the XRD (102 ) FWHM is less than 150 arc seconds. A GaN-based electronic device includes: a substrate; and an aluminum nitride (AlN) buffer layer, the AlN buffer layer is located on the substrate, and an oxygen concentration of the AlN layer is between 1E18 and 1E23cm ^-3 . The GaN-based electronic device according to claim 15, wherein the device is one selected from the group consisting of a field effect transistor (FET) and a power supply device. The GaN-based electronic device according to claim 15, wherein a part of the oxygen system includes an AlN / substrate interface. The GaN-based electronic device according to claim 15, wherein a part of the oxygen system is included on an outermost surface of the AlN buffer layer. The GaN-based electronic device according to claim 15, further comprising: a high-quality GaN layer on the AlN buffer layer, and the XRD (002) FWHM of the high-quality GaN layer is less than 100 arc seconds and XRD (102) FWHM is less than 150 arc seconds. A chamber for forming an aluminum nitride (AlN) buffer layer for a GaN-based optoelectronic or electronic device, the chamber includes: a pumping system and a chamber cooling design to achieve 1E-7 Torr or less High background vacuum, and low rise rate at high temperature; a comprehensive erosion of the magnetron cathode, configured to allow an AlN film to have consistent target erosion and uniform deposition throughout the wafer; The processing kit and the airflow design are configured so that the process gas including the O-containing gas is uniformly distributed in the chamber to obtain a uniform AlN composition; and an oxygen-doped Al target. The chamber of claim 20, further comprising: a high-temperature biasable electrostatic chuck configured to rapidly and uniformly heat a plurality of wafers. The chamber according to claim 20, wherein a vacuum rise rate of the chamber is 2500 Nato / min or less. The chamber of claim 20, wherein the high temperature is about or higher than 350 ° C.